Aim. To provide preliminary data about the efficacy of omega-3FA in the treatment of adolescent MDD. To address this aim, a 10-week double blind, placebo-controlled study of omega-3FA, using a flexible dose titration is proposed. Primary outcome measures will be: (1) change in the total score of the Children's Depression Rating Scale-Revised (CDRS-R) at the end of treatment (2) response rate on the Clinical Global Improvement scale (CGI) at the end of 10-week treatment.